Question

prove that

cos 45 . cos 30 - sin 45 . sin 30 = cos75


plz answer fast​

Answer 1

Answer:

cos75=cos75 hence proved

Step-by-step explanation:

cos45. cos30 - sin45. sin30 = cos75

solution-

by formula-

cos(a+b) = cos a .cos b - sin a. sin b

taking left hand side-

cos(45+30) = cos 45.cos 30 -

sin45.sin30

cos75. proved right hand side